Embodiments of the present invention relate to a photodetector array, and more particularly, to a photodetector array using isolation diffusions as crosstalk inhibitors between adjacent photodiodes and a method for manufacturing a photodetector array using isolation diffusions.
A photon detector or photodetector (also called a photodiode) converts radiant power or light directly into electrical current. Positive-intrinsic-negative (PIN) diodes or PIN photodiodes are generally known in the art. A PIN/NIP diode is a form of photodetector.
A PIN diode is a type of photodiode with a large, neutrally doped intrinsic region sandwiched between p-doped and n-doped semiconducting regions. The PIN diode's name comes from the layering of these materials positive, intrinsic, negative (PIN). Broadly speaking, a photodiode is a semiconductor device that converts light to electrical current. A PIN diode typically exhibits an increase in its electrical conductivity as a function of the intensity, wavelength, and modulation rate of the incident radiation or light.
A PIN diode is also a semiconductor device that operates as a variable resistor at radiofrequency (RF) and microwave frequencies. The resistance value of the PIN diode is determined only by the forward biased direct current (DC) current. At high RF frequencies when a PIN diode is at zero or a reverse bias, it appears as a parallel plate capacitor, essentially independent of the reverse voltage.
Photoconductor arrays are groups of a plurality of photodetectors, such as PIN/NIP diodes, arranged together on a substrate or wafer. Crosstalk between photodiodes is seen when the light detection and conversion process of one photodiode affects the detection and conversion processes of adjacent photodiodes. Prior art methods of eliminating crosstalk involved forming dielectric filled trenches to isolate adjacent photodiodes from one another.
It is desirable to provide a photodetector array using isolation diffusions to eliminate the need to form another set of trenches in the semiconductor substrate. Further, it is desirable to provide a photodetector array using isolation diffusions as crosstalk inhibitors between adjacent photodiodes.